Tamping tool



Jan. 30, 1934. H s, BRQWN 1,945,132

TAMPING TOOL Filed Jan; 9, 1951 2'Sheets-Sheet l .Im 3o, 1934. l H. s. BR'OWN 1,945,132

' TAMPING TooL Filed Jan. 9, 1931 2 sheets-sheet 2'.

/729/2 Proa/ 172 (Qt/(nass Patented Jan. 30, 1934 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to portable vibratory tools such as rock drills, tampers and other similar devices designed to be handled and controlled by a single operator.

In devices of this character it is desirable to have them operate as efliciently as possible, that is, with the use of as little power as possible Vand to have as little vibration as possible. Heretofore it has been the practice to provide a vibrating hammer head and to actuate this head either directly in both directions by mechanical means or by some compressible fluid such as air.

This invention is an improvement upon the latter type of tool. As heretofore made this type of tool employed a compressed fluid as the driving force, the fluid being supplied from some suitable source separate and distinct from the hammer head. The fluid from this source, put under suitable pressure by an external compressor, was admitted at the desired pressure into the cylinder behind the hammer head. A certain amount of the air thus admitted into the cylinder was also trapped therein to also serve as a cushion to retard the final movement of the hammer head upon its return stroke.

I have discovered that the entrapped fluid usually employed merely to cushion the hammer head may also advantageously be employed to impart working movements to the hammer head.

Therefore, according to this invention, the ham mer head itself is reciprocated to build up and impart a working pressure to a certain amount of entrapped air within the hammer cylinder,

. without the use of separate air supplies and extraneous pressure building devices to impart working movements to the hammer head. By this improvement many otherwise necessary working parts may be eliminated and the entire mechanism reduced to the simple essentials. Vibrations are also reduced due to the eliminationof a number of vibrating elements without sacrificing any such elementsV which of themselves may tend to reduce vibrations. Means are also provided whereby working pressures may be varied or adjusted to various degrees.

Other novel features of this invention and their resulting advantages will be apparent from the following description given in connection with v the drawings, in which.;

Fig. 1. is a vertical section through approximately the center of av vibratory tool omitting the working end of the tool member itself.

Fig. 2 is a horizontal section taken` on line 2--2 of Fig. 1.

Fig. 3 is a side elevation of a rocking member.

Fig. 4 is a side elevation of the helve.

Fig. 5 is a side elevation of the connecting link.

Fig. 6 is a side elevation of a piston hammer head, and

Fig. 'Z is a front elevation of the yoke niem-v ber.

Referring to the embodiment of this invention' illustrated in the drawings, it will be seen that the entire mechanism with the exception of the driving motor and actuated tool is encased within a housing 1, the latter being closed at its upper end by a cover plate 2, which may be secured to the housing by suitable bolts or the like, (not shown). The cover plate 2 is provided with an upwardly extending cylindrical boss 3 which serves as a support for the upper end of the cylinder sleeve, later to be described, and to which is secured a handle connection 4, the latter being flanged and secured to the upper flanged end of the circular boss. A rubber insulator 6 may be inserted between the handle connection and the end of the cylindrical boss to prevent the trans-I mission of vibrations thereto. The cover member 2 is also provided with a laterally projecting bracket 7 to which may be secured a handle 8. The tool may readily be manipulated through the medium of the two handles.

The casing proper is provided upon one side thereof with a circular cylindrical portion 9 within which is seated a cylinder sleeve 11 which serves as a cylinder for the piston-like hammer head 12`. The lower end of the cylinder 9' is enlarged as at 13 to receive a bushing 14 havd ing a hexagonal bore which serves' as a bearing for the upper hexagonal end of the vibrating tool 15. Bushing 14 also acts as a retainer for the cylinder sleeve 11 against the lower end of which it contacts. Bushing 14 is retained in place by an end cap 16 secured to enlarged end 13 by .95y cap screws or the like 17. Bushing 14 is pre` vented from rotating by a key 18a whichy locks the bushing to the enlarged end 13. A split bush-A ing 18 serves as a guide or bearing for the pro-I jecting end of the vibrating' tool 15 and also serves to limit the downward movement of the vibrating tool by engagement with a collar 21 formed on the tool. A pad of rubber 20 is placed around the tool between the collar 21 and the inner end of bushing 18 to resiliently urge the tool to its upper position.

Formed integrally upon the wall of the casing oppositev to that of the cylindrical portion 9 are two interior bosses 22 and 23v within which is se# cured a pivot pin or bolt 24 provided upon one end with a head 26 and grease fitting 27 and upon the other end with a oastellated nut 28. Pin 24 serves as a fulcrum for the end 29 of a lever or helve 30 the free end of which is formed to a partial sphere 31. The free or spherical end 31 of the helve extends through a slot 32 formed in the side of sleeve 11 and engages a suitable recess formed in the hammer 12 whereby the helve may impart reciprocal movements to the hammer 12.

Reciprocal movements are imparted to the helve through the medium of a bifurcated rocker member 33 having a pair of circular ears 34 which lie upon each side of end 29 of the helve and which are bored to receive pin 24. The upper portion 36 of the rocker 33 is bored and threaded to receive a cup member 37 the latter of which has an apertured bottom to permit the passage of the round shank portion 38 of a yoke 39.

The yoke 39 as can be seen from Fig. 1 surrounds the helve at a point adjacent the pivoted end thereof.V The yoke is so positioned and the opening therethrough is of suicient size to permit of lost motion or play of the helve within the yoke so that the yoke will raise the helve upon its upward movement but will not normally lower the helve. The yoke is resiliently connected to the rocker to yield in one direction relatively'to the rocker member. This resilient connection comprises a flanged sleeve 41 which engages the shank portion 38 of the yoke and is secured thereon by a nut 42. A compression spring 43 is disposed within the cup 37 and maintained under compression by the flanged sleeve 41 and the bottom of the cup 37. The flanged end of the sleeve 41 is of sufficiently small diameter to permit its movement into the cup.

'Ihe rocker 33 is oscillated in the illustrated embodiment by an electrical mo-tor 44 secured within a concaved surface of the Ahousing by a strap 45 although any suitable source of power may be utilized. The yarmature shaft 46 of the motor carries a spur gear 47 which meshes with a larger -sp-ur gear 48 keyed to the crank shaft 49 having a crank pin 51 formed upon one end thereof. Shaft 49 is journalled in bearings 52 and 53 the former being supported in an interior boss 54 formed in the casing and the latter being secured in a bearing cap 56 secured to an outer wall of the casing 1. A connecting rod or link 57 is provided with a bearing 58 at one end engaging crank pin 51. The other end of link 57 is journalled upon a pin 59 secured to the upper end 36 of rocker 33.. .Rotation of shaft 49 and its crank pin 51 will therefore imp-art oscillatory movements to rocker 33 through the medium of connecting rod 57. Rocker 33 will raise yoke 39 and helve 31 which in turn will throw the piston hammer head 12 upwardly to compress the entrapped air drawn in through the slot or port 32 in the upper or closed end of the cylinder Ito a working pressure. The compressed air will force the piston hammer downwardly in a driving or working blow against the upper end of tool 16. The crank pin by this time has of course rotated into its lowermost position which will lower rocker 33 and yoke 39 to permit the downward movement of helve 31 and hammer l2. It has been found that in some instances the throw of the hammer carries the helve ahead of the yoke so that the latter does not contact with the helve for'its full upward stroke.

Means are provided for controlling and regulating the degree of compression of the entrapped air. For this purpose the upper end of cylinder sleeve 11 has a cap 61 threadedly secured thereto,

the latter being bored to receive a threaded plug 62 which may be locked in adjusted position by a lock nut 63. It is obvious therefore that by varying the position of plug 62 the degree of compression may be adjusted to suitable limits. The size and position of port 32 also determines in part. the amount of air discharged as the piston clears the upper end thereof and controls in part the amount of air taken in due to suction created as the piston continues its downward stroke after clearing ythe upper end thereof.

In order to lubricate the cylinder, an oil or grease well 64.is formed within the wall of the casing adjacent the cylinder and runs longitudinally with respect to the cylinder. This well is provided with inlets 66 whereby it may be supplied from without and with ducts 67 which communicate with the interior of the cylinder for lubricating the same.

From the foregoing it will be apparent that the piston hammer head is utilized to compress the entrapped air within the cylinder -which is ported to the atmosphere through slot 32 to working pressures and that the entrapped compressed air is used to impart a driving blow to the hammer head. The piston is free upon its downward stroke, that is, is not cushioned by compressing any air nor is it restricted by the creation of a partial vacuum. In other words, the piston is free to be actuated by the full force of the air compressed in the upper or closed end of the cylinder. The motor and associated operative connections Iare utilizedonly to raise the hammer head -to compress the entrapped air but not to impart a driving or working blow to the hammer head.

The resilient connection of the yoke and the resilient connection of the upper handle are additional features which reduce the vibrations transmitted to the frame and to the operator. It is apparent of course that the very operation of the device itself inherently reduces the vibrations to a minimum.

It is also apparent that the aforedescribed construction employs no valves, does not cushion the downward stroke nor is it restricted by the creation of a partial vacuum, and does not cause any work to be done by the piston on its downward stroke such as by by-passing or preliminarily compressing the air. The construction is not only `simple to manufacture, convenient to operate, but is rugged and enduring. lTheparts are readily accessible for inspection, renewal or repair.

It is obvious that many changes may be made without departing from the spirit and scope of this invention as defined in the claims.

I claim: y

1. In a portable power vibratory tool, a portable casing having a cylinder therein hermetically sealedat one end and ported to the atmosphere adjacent its other end, a piston hammer reciprocable in said cylinder, a pivoted helve having its free end connected to said piston hammer and means for rocking said helve about its pivot at a relatively high frequency, said means comprising a source of power carried by said casing and a mechanical connection therefrom to said helve, said connection being yieldable in one direction and having lost motion in the other direction to limit the rocking movement imparted to said helve to one direction to cause said piston hammer to compress the entrapped air in said cylinder to a working pressure and force said piston hammer in a working direction.

2. In a portable power vibratory tool, a portibo iro

able casing having a cylinder therein hermetically sealed at one end and ported to the atmosphere adjacent its other end, a piston hammer reciprocable in said cylinder, a pivoted helve having its free end connected to said piston hammer, a pivoted rocker member connected to said helve and means carried by said casing for rocking said rocker member at a relatively high frequency 'to raise said helve to cause said piston hammer to compress the entrapped air in the closed end of said cylinder to a working pressure to force said piston hammer in a working direction, said means comprising a source of power and a mechanical connection therefrom to said helve, said connection being yieldable in one direction and having lost motion in the other direction.

3. In a portable power vibratory tool, a portable casing having a cylinder therein hermetically sealed at one end and ported to the atmosphere adjacent its other end, a piston hammer reciprocable in said cylinder, and means carried by said casing having a lost motion connection and engaging said piston hammer for intermittently raising said piston hammer and throwing it freely into the closed end of said cylinder to cause the hammer to compress the entrapped air in the closed end of the cylinder to a working pressure to force said piston hammer out of said closed cylinder end in a working direction, said cylinder being opened to the atmosphere during the iinal portion of the working movement of said piston hammer by the movement of the hammer entirely into the ported end of the cylinder to permit it to move freely and without restriction in its working direction.

li. n a portable power vibratory tool, a portable casing having a cylinder therein hermetically sealed at one end, a piston hammer reciprocable in said cylinder, a pivoted helve having one end connected to said piston hammer, said cylinder being slotted to permit sliding movement of the helve therein and to port the cylinder to the atmosphere adjacent its other end, and means carried by said casing and connected through a lost motion connection to said helve for intermittently raising said helve at a relatively high frequency to throw the hammer freely into the closed end of the cylinder to cause the piston hammer to compress the entrapped air in said cylinder to a working pressure to force said hammer out of said closed cylinder end in a working direction, said cylinder being opened to the atmosphere during the final portion of the working movement of the hammer by the uncovering of the end of the slot adjacent said closed end of the cylinder to permit the hammer to move freely and Without restriction in its working direction.

5. In a portable power vibratory tool, a portable casing having a cylinder therein hermetically sealed at one end and ported to the atmosphere adjacent its other end, a piston hammer reciprocable in said cylinder, a pivoted helve having its free end connected to said piston hammer, and means for rocking said helve about its pivot at a relatively high frequency, said means comprising a source of power carried by said casing and mechanically connected therefrom to said helve, said connection having lost motion in one direction to limit the rocking movement imparted to said helve to cause said piston hammer to compress the entrapped air in said cylinder to a working pressure and force said piston hammer in a working direction, said piston hammer and cylinder being constructed and arranged to effect no retarding action on said hammer during the iinal movement of the latter in its working direction.

6. In a portable power vibratory tool, a portable casing having a cylinder therein hermetically sealed at one end and ported to the atmosphere adjacent its other end, a piston hammer reciprocable in said cylinder, a pivoted helve having its free end connected to said piston hammer, a pivoted rocker member connected to said helve through a yieldable, lost motion connection and means carried by said casing for rocking said rocker member at a relatively high frequency to raise said helve to cause said piston hammer to compress the entrapped air in the closed end of said cylinder to a Working pressure to force said piston hammer in a working direction, said means comprising a source of power and a mechanical connection therefrom to said rocker member.

"l. In a portable power vibratory tool, a portable casing having a cylinder therein, a piston hammer reciprocable in said cylinder, and means for reciprocating said piston hammer to cause the latter to compress the air entrapped in said 120 cylinder to a working pressure for forcing said piston hammer in a working direction, said means comprising a source of power carried by said casing and a mechanical connection therefrom to the piston hammer, said connection being yield- 125' able in one direction and having a lost motion in the other direction.

HUGH s. BROWN. 

